Support is requested for organizing the third conference on Hemoglobin Switching. The conference is planned to take place in Seattle, Washington, in June, 1982. It will represent a gathering of molecular biologists, cell biologists, developmental biologists and clinical investigators who are directly involved with studies on hemoglobin switching and the regulation of erythropoiesis during development. The duration of the conference will be four days. Sessions include a) organization of globin genes and regulation of globin gene expression, b) developmental biology of fetal hemoglobin, c) regulation of erythropoiesis during development, d) biology of established human hemoglobin synthesizing lines. International participation is anticipated and support for travel and/or lodging expenses for 12 foreign and 30 USA participants is requested.